1. Field of the Invention
The present invention relates generally to a check valve, and particularly to a check valve such as may be used on a reclosable thermoplastic pouch.
2. Description of the Background of the Invention
Food or other perishables are often stored in reclosable thermoplastic pouches. To keep food stored inside a pouch fresh for an extended period, a user may evacuate air out of the pouch after completely sealing the pouch using a closure mechanism.
One pouch for packaging of granular solids and small articles is filled and then sealed. The pouch has an interrupted seam between opposing panels of the pouch. The interrupted seam separates a small portion of the pouch from a larger pouch interior. A continuous seam between the opposing pouch panels is disposed proximate to the interrupted seam on a side of the interrupted seam opposite the pouch interior. The opposing pouch panels are flattened between the seams, and an aperture is disposed through one of the opposing pouch panels. Air trapped within the pouch interior during sealing of the pouch may be expelled through the interrupted seam and out of the pouch through the aperture, wherein the flattened panels between the seams act as a valve against the ingress of air.
A further pouch for packaging contents that generate gases is filled and then sealed. The pouch has an interrupted seam between opposing panels of the pouch, wherein the seam is parallel to and proximate to an edge of the pouch. A continuous seam between the opposing pouch panels is disposed between the interrupted seam and the edge of the pouch. A path is defined from a pouch interior to a pouch exterior extending through the interrupted seam and around the ends of the continuous seam. A plurality of puckers is disposed in the material of the opposing panels along the path. The puckers cause the opposing panels to be in contact, thereby effectively forming a normally closed valve. Air within the pouch having an elevated pressure relative to the atmosphere may separate the puckers to escape the pouch, however air from the atmosphere is prevented from entering the pouch.
Another pouch has portions of opposing panels that protrude outwardly from a side of the pouch. The outwardly protruding portions are sealed to one another to form a channel that has a closure mechanism that may be sealed independently from a main closure mechanism disposed across a main pouch opening. The channel may be used to evacuate or to inflate the pouch after the main closure mechanism is sealed.
Yet another pouch has a conduit that extends from an edge of the pouch, wherein the edge is otherwise sealed by a main closure mechanism in juxtaposition with the conduit. The conduit allows communication between an interior of the pouch and an exterior of the pouch for evacuating the pouch after the main closure mechanism is sealed. The conduit has a sealing mechanism that is normally open but that may be squeezed closed to seal the conduit after evacuation of the pouch.
Still another pouch has a first closure mechanism disposed parallel to and proximate to an open end of the pouch. A second closure mechanism is disposed between the first closure mechanism and a closed end of the pouch, and defines a pouch interior. A venting aperture is disposed through the first closure mechanism and at least one panel of the pouch immediately proximate the first closure mechanism. The venting aperture defines a passageway for air between the pouch interior and an exterior of the pouch when the second closure mechanism is open, and the second closure mechanism may be sealed after the pouch is vented through the aperture.
Yet another pouch has a check valve disposed in an end of the pouch opposite a closure mechanism. The check valve has two rectangular narrow films of material sealed together to form a tube, wherein the tube is disposed between opposing panels of the pouch such that one end of the tube is within a pouch interior and a second end of the tube projects outside of the pouch interior. The tube further has a folded piece of film material sealingly disposed within the tube. Air within the pouch having an elevated pressure relative to an exterior of the pouch may separate the folds of the folded film material and escape through an aperture therethrough; however, air is prevented from flowing into the pouch interior by the folded film material. The opposing pouch panels are extended and sealed together around a periphery thereof to cover the second end of the tube, leaving an unsealed gap for air to escape to the atmosphere.
A pouch having a normally open valve or a vent may allow contents of the pouch to escape from the pouch. Further, a valve or vent proximate the closed end of a pouch is more likely to leak contents because contents placed into the pouch through a main opening typically settle to a closed end of the pouch. Consequently, excess air within the pouch is most effectively evacuated through the main opening.